1. Field of the Invention
This invention relates to an optical mechanism comprising: an optical beam generating mechanism to generate an optical beam; and a unitary, transparent waveguide for guiding the optical beam to an optically writable surface wherein optical elements for guiding the optical beam are coated onto the waveguide to create a relatively compact optical system, a relatively low exit numerical aperture for the exit pupil, and for bending and re-directing the optical beam.
2. Description of the Related Art
Prior to the present invention, as set forth in general terms above and more specifically below, it is known that optical disc drives have historically been used to optically read data from and optically write data to data regions of optical discs. More recently, optical disc drives have been used to optically write images to label regions of optical discs. For example, a type of optical disc is known in which a laser or other optical beam can be used to write to the label side of an optical disc.
A costly component of an optical disc drive is the optical pickup unit (OPU). The OPU is the optical mechanism by which an optical beam is generated, and then guided to the surface of an optical disc using a number of precisely arranged lenses and other components, including an objective lens, which have to be manufactured to high tolerances, and thus at high cost. Therefore, optical disc drives typically only have one OPU for cost and complexity reasons. An optical drive having just a single such optical mechanism for accessing both the label and the data sides of an optical disc, however, forces a user to remove the disc from the drive, flip it over, and reinsert the disc back into the drive when the optical drive needs to access the data side after having accessed the label side, and vice-versa. Consequently, a more advantageous optical disc drive, then, would be provided if only one OPU could be utilized.
It is also known, that conventional optical print heads (OPHs) use a non-waveguide optical path in the optical disk drive. The non-waveguide optical path can be constructed of plastic or metallic materials. The discrete optical components (objective lens, collimator, prism, and quarter wave element) are then cemented to the non-waveguide arm or optical pick-up unit (OPU)-sled assembly. The alignments of these optical components are very critical to the quality of the OPH. Also, the alignments can be costly as well as time consuming. Therefore, a further advantageous OPH, then, would be provided if a glass/quartz (or any high transmit and low birefringence material for labeling wavelength) are could be used in the OPH for disk labeling.
It is further known to use a unitary wave guide arm wherein optical elements are secured to the wave guide to provide the necessary reflection/refraction surfaces. As discussed above, the optical elements alignments and optical beam generating mechanism alignments are very critical to the quality of the OPH. Also, the alignments can be costly as well as time consuming. Finally, these type of wave guides utilize an extremely long path length.
It is apparent from the above that there exists a need in the art for a unitary, transparent glass/quartz (or any high transmit material for labeling wavelength) waveguide that utilizes optical elements that are placed onto the waveguide such that the waveguide creates a more compact assembly, employs a relatively low numerical aperture for the exit pupil that can be used in the OPH for disk labeling, and reduces the number of alignments. It is a purpose of this invention to fulfill this and other needs in the art in a manner more apparent to the skilled artisan once given the following disclosure.